1. Field of the Invention
This invention is in the field of controls for air conditioning systems, and more particularly relates to an improved duty cycle controller for such systems.
2. Description of the Prior Art
The use of timers to alternately switch the compressor of an air conditioner on and off, or to provide it with a duty cycle while the thermostat of the air conditioning system is calling for cooling, or producing a cooling signal, is known. However, problems with such timers, or duty cycle controllers, are that the duty cycle timer is not synchronized with the energization signals; i.e., a cooling signal, produced by the thermostat so that if the thermostat is producing a cooling signal when the timer is in its off position, or nonenergization phase, several minutes may elapse before the desired heating or cooling function of the air conditioner is energized. During this time interval, the fan of the air conditioner will be energized so that hot air from the air conditioner will be circulated into the space to be cooled until the timer is in its on phase. This, of course, adds to the discomfort rather than providing the desired correction to the temperature of the space whose air is being conditioned.
Another problem with prior art controllers is that they provide no protection against damage to the compressor of the refrigeration unit, or of a heat pump caused by restarting the compressor before all the liquified refrigerant that may have drained into the compressor has vaporized. Starting a compressor with liquified refrigerant in it, will destroy the compressor.